Control apparatus for vehicular power transmitting system

Abstract

A control apparatus for a vehicular power transmitting system including an electrically controlled differential portion having an electric motor, and an automatic transmission portion, the control apparatus including shift control portion operable upon determination that a jump shift-down action of the automatic transmission portion directly to a target gear position while skipping at least one intermediate gear position should take place and upon inhibition of the jump shift-down action, to generate a shifting command to perform the jump shift-down action when total jump-shift-down-action time required for the jump shift-down action is shorter than total sequential-shift-down-operation time required for a sequential shift-down operation consisting of a shift-down action to each intermediate gear position and a shift-down action from the last intermediate gear position to the target gear position, and a shifting command to perform the sequential shift-down operation when the total jump-shift-down-action time is not shorter than the total sequential-shift-down-operation time.

1. A control apparatus for a vehicular power transmitting system including (a) an electrically controlled differential portion having a differential mechanism disposed between an engine and a drive wheel, and a differential-portion electric motor operatively connected to the differential mechanism, wherein a differential state of the differential portion is controllable by controlling an operating state of the differential-portion electric motor, and (b) a step-variable automatic transmission portion which constitutes a part of a power transmitting path between the engine and the drive wheel, said control apparatus comprising:
 a shifting-action determining portion configured to determine whether a shifting action of the automatic transmission portion should take place; 
 a shifting inhibiting portion configured to inhibit a shift-down action of the automatic transmission portion when an operating speed of the engine is lower than a predetermined lower limit; 
 a shifting-time comparing portion operable when said shifting-action determining portion determines that a jump shift-down action of the automatic transmission portion from a present gear position to a target gear position while skipping at least one intermediate gear position therebetween should take place, and when said jump shift-down action is inhibited by said shifting inhibiting portion, said shifting-time comparing portion being configured to compare a total sequential-shift-down-operation time required for a sequential shift-down operation consisting a shift-down action from the present gear position to each of said at least one intermediate gear position and a last shift-down action from the last intermediate gear position to said target gear position, with a total jump-shift-down-action time required for said jump shift-down action to be performed after the inhibition of said jump shift-down action is canceled; and 
 a shift control portion operable when said shifting-action determining portion determines that said jump shift-down action should take place and when said jump shift-down action is inhibited, said shift control portion being configured to generate a shifting command to perform said jump shift-down action when said total jump-shift-down-action time is shorter than said total sequential-shift-down-operation time, and a shifting command to perform said sequential shift-down operation when said total jump-shift-down-action time is not shorter than said total sequential-shift-down-operation time. 
 
     
     
       2. The control apparatus according to  claim 1 , wherein said total sequential-shift-down-operation time is a length of time from a moment of determination that said jump shift-down action should take place, to a moment at which said sequential shift-down operation is completed, while said total jump-shift-down-action time is a length of time from said moment of determination to a moment at which said jump shift-down action is completed. 
     
     
       3. The control apparatus according to  claim 1 , further comprising a shifting-inhibiting-time estimating portion operable when said shifting-action determining portion determines that said jump shift-down action should take place and when said jump shift-down action is inhibited by said shifting inhibiting portion, said shifting-inhibiting-time estimating portion being configured to estimate, on a basis of a change of an operating speed of said engine, a jump-shift-down-action inhibiting time from a moment of determination that said jump shift-down action should take place, to a moment at which inhibition of said jump shift-down action by said shifting inhibiting portion is canceled,
 and wherein said shifting-time comparing portion determines a sum of said jump-shift-down-action inhibiting time and a length of time from a moment of initiation of said jump shift-down action to a moment of completion of said jump shift-down action, as said total jump-shift-down-action time. 
 
     
     
       4. The control apparatus according to  claim 1 , wherein said predetermined lower limit of the operating speed of the engine is determined to prevent a rise of an absolute value of the operating speed of said differential-portion electric motor above a permissible highest value, such that the lower limit increases with an increase of a speed ratio of the gear position to be established by and after said shifting action to be inhibited by said shifting-action inhibiting portion.